Reaction Steps
Following the procedure as described in EXAMPLE 4 and making non-critical variations using (R)-3-bromomethyl-2-pyrrolidinone to replace 2-(bromomethyl)tetrahydro-2H-pyran, and spiro[furo[2,3-f][1,3]benzodioxole-7,3′-indol]-2′(1′H)-one to replace 5,6-dihydrospiro[benzo[1,2-b:5,4-b′]difuran-3,3′-indol]-2″(1H)-one, 1′-{[(2S)-5-oxopyrrolidin-2-yl]methyl}spiro[furo[2,3-f][1,3]benzodioxole-7,3′-indol]-2′(1′H)-one was obtained (47%) as a colorless solid: mp 121-130° C.; 1H NMR (300 MHz, CD3OD) δ7.34 (dd, J=7.6, 7.6 Hz, 1H), 7.22-7.06 (m, 4H), 6.48 (d, J=1.9 Hz, 1H), 6.15 (d, J=9.3 Hz, 1H), 5.82 (d, J=1.4 Hz, 2H), 4.86-4.81 (m, 2H), 4.64 (dd, J=9.3, 3.8 Hz, 1H), 4.13-4.06 (m, 1H), 3.85-3.83 (m, 2H), 2.43-2.18 (m, 2H), 2.00-1.88 (m, 1H); 13C NMR (75 MHz, CD3OD) δ177.9, 177.4, 177.3, 154.7, 154.6, 147.5, 147.4, 141.2, 140.8, 140.8 136.0, 130.8, 130.6, 127.3 127.2, 127.0, 126.3, 123.4, 122.0, 121.9, 121.9 118.0, 117.8, 107.4, 101.1, 100.0, 99.9, 91.3, 91.3, 78.8, 78.7, 56.8 (2C), 51.4, 51.2, 43.2 (2C), 27.6, 22.6, 18.6; MS (ES+) m/z 401.2 (M+23), 379.2 (M+1).
